Exercise sole

ABSTRACT

An improved exercise device including a sole with an upper surface on which a wearer&#39;s foot rests and a lower partially ground contacting surface. The sole has a heel, a midfoot, a forefoot and a toe region such that when the heel region lower surface and the forefoot region lower surface are in ground contact, the upper surface does not incline upwards from the forefoot to the heel region. The forefoot lower surface of the sole is generally radiused in a cylindrical curve about the line connecting the mid points of the first and second metatarsal-phalangeal joints of the wearer. When the wearer contracts their calf muscles, the heel section is lifted away from the ground, requiring work against gravity.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Whatley, U.S. ProvisionalApplication 60/037,652, entitled “Exercise Sole”, filed Jan. 22, 1997,which is hereby incorporated herein by reference in its entirety,including any drawings and figures.

BACKGROUND OF THE INVENTION

[0002] This invention relates to soles for an article of footwear,specifically to an improved exercise-providing sole for an article offootwear.

[0003] The discussion below is provided to assist the understanding ofthe reader. None of the information provided or references cited isadmitted to be prior art to the present invention.

[0004] Jumping, running, plyometric exercise and power walking havegrown in popularity over the last few years. Footwear and overshoes havebeen designed to improve muscle conditioning during these movements byincreasing the angle through which the ankle flexes. This works the calfmuscles through a more full range of motion than is possible intraditional footwear. The effect is achieved by placing the verticallythickest section of the sole forward of the heel.

[0005] Some soles have been designed providing a rocker structure withan elevated heel. Examples of this include Famolare, U.S. Pat. No.3,936,956, Daswick, U.S. Pat. No. 4,241,523 and Spronken, U.S. Pat. No.4,425,721.

[0006] Some references describe a sole with a thicker section forward ofthe heel without a rocker structure. This structure has been associatedwith a forefoot to ground slapping motion which may cause injury to thewearer. Examples of this include Monier, U.S. Pat. No. 2,769,252, Cox,U.S. Pat. No. 3,739,500 and Nakamoto, U.S. Pat. No. 3,859,727.

[0007] Other structure are described in which the thickest verticalsection of the sole is behind the metatarsal heads. Examples of thisstructure include Newell, U.S. Pat. No. 3,802,424, Phillips, U.S. Pat.No. 4,155,180 and Bunke, U.S. Pat. No. 4,811,504.

[0008] Other structures are described that place a vertically thickestsole section forward of the distal metatarsal joints of a wearer's foot.Examples of this include Wenker, U.S. Pat. No. 2,172,000 and Baker, U.S.Pat. No. 3,472,508.

[0009] A number of alternative radii and alignments of sole structurehave been described. For example, Kalsoy, U.S. Pat. No. 3,305,947describes a sole structure having a curved bottom to transfer weightfrom the outer portion of the heel to the big toe during a step,Banister, U.S. Pat. No. 2,283,595 describes a stilt structure attachableto shoes which has a compound curve on the lower surface, Witherill,U.S. Pat. No. 2,328,242 describes a sole structure which has generallythe contours of a human foot, and Urban, U.S. Pat. No. 2,519,613describes a protective device which is attachable to a shoe sole andwhich prevents contact of the toe of the shoe with the ground duringnormal walking.

SUMMARY OF THE INVENTION

[0010] This invention provides soles for shoes which allow a full rangeof motion for the calf muscles in exercise, provide a continuous rollingmotion for the forefoot, provide a forefoot rolling action aligned withthe primary point of force exertion in jumping and provide a forefootsole radius length appropriate for exercise of the calf muscles.

[0011] The soles of this invention can also reduce the forefoot toground slapping action, allow grading of the sole radius according tofoot dimensions and reduce the abrasion wear which occurs in relativelyflat soles.

[0012] The peak pressure in jumping off the ground is exerted betweenthe first and second metatarsal bones at their joints with thephalanges. These are two hinge joints with a common axis oriented atabout 90° to the longitudinal axis of the shoe sole in a plane aboutparallel to the ground. In order to permit a smooth contraction of thecalf muscle during exercise, the ground contacting surface of the soleshould form a cylindrically curved surface radiused about a linegenerally connecting the midpoints of the first and secondmetatarsal-phalangeal joint. It is preferable that the cylindricallycurved portion of the ground contacting surface is a curve of a circularcylinder, however, the curvature need only approximate that shape. Thus,the curvature may be slightly elliptical or of variable or othercurvature which approximates a circular curvature.

[0013] Thus, the invention features a sole structure for attachment toan upper to form an article of footwear or for attachment to an existingarticle of footwear.

[0014] The term “sole” is used, as the term is commonly used, to includeall those elements of an article of footwear which are attached belowthe upper. These may typically include such items as a midsole, anoutsole, shock attenuating components and stabilizing components.

[0015] The term “upper” is used to denote those pieces and components ofa shoe that cover the foot above the sole. In the context of thisinvention it includes any structure adapted for engaging the foot or anexisting shoe in such a fashion as to hold the disclosed sole on thefoot of a wearer. An upper may include such things as a lace closed bagof material, a series of straps or a sheet of contact adhesive.

[0016] The sole has an upper surface on which the wearer's foot restsduring use of the sole. The wearer's foot may be placed directly on thesole or may be separated by layers of material such as a lasting board,sockliner or other components. The wearer's foot may also be displacedabove the upper surface of the sole by an existing shoe, as would be thecase when the sole is attached as an overshoe to enhance exercise whenmore traditional footwear is being worn. The sole may have side wallsthat extend above the plane of the upper surface, as would be the casewhen a foam midsole forms a wrap onto an upper or a rubber cupsole isprovided.

[0017] The sole has a lower surface which may be adapted for groundcontact such as by the inclusion of abrasion resistant solid rubber onthe surface or the provision of a ground gripping tread or cleatconfiguration.

[0018] The sole is invisibly divided into regions according to theoverlying parts of a wearer's foot during use. These regions are theheel, the midfoot, the forefoot and the toe area. The sole upper surfacehas a rear edge and a front edge. The length of a sole is the distancebetween the front and rear edges of the upper sole surface measuredlinearly along the longitudinal axis.

[0019] The heel region is generally below a wearer's calcaneous and isapproximately the rear 20-30% of the sole length (from 0% to about20-30%). The midfoot is the region forward of the heel but behind theregion corresponding to the ball of the foot which is referred to as theforefoot. The midfoot extends about from 20-30% to 55-60% of the solelength measured from the rear edge of the sole upper surface. Theforefoot is about 55-60% to 85-90% of the length of the sole from therear edge of the sole upper surface. The toe region includes the solearea below the phalanges of a wearer and any additional sole materialforward of this region. It extends from 60-85% to 100% of the solelength from the rear edge of the sole. The variation in the position ofregions is due to individual differences in the proportions of footparts of wearers. For the above locations of the regions of a sole, thespecified percentages refer to approximate beginning and ending pointsof each region, specified as the percentage of the distance from theterminal heel point to the terminal toe point. Thus, for example, themidfoot extends about from a point which is about 20-30% of the distancefrom the rear edge to the front edge of the sole, to a point which isabout 55-60% of the distance from the rear edge to the front edge of thesole.

[0020] Naming invisible regions does not indicate a need for the sole tophysically extend through these areas, since the forefoot region is theonly area where material must be included for the sole to function incertain preferred embodiments.

[0021] The sole has a longitudinal axis defined by a line generallyconnecting the mid points of the heel and forefoot regions of the soleor connecting their extrapolated positions if these regions are notphysically present. The horizontal width of the sole is measured atabout 90° to the longitudinal axis and parallel to the ground. Thevertical thickness is measured at about 90° to the longitudinal axis andabout 90° to the ground.

[0022] The sole has a thickness between the upper and lower surfacesalong the longitudinal axis. This thickness is at a maximum in theforefoot region. Thus, the lower surface of the heel and forefoot of awearer will be parallel to the ground or the heel will be lower than theforefoot when the forefoot lower surface of the sole is in groundcontact and the wearer's foot urges the heel region onto the ground.

[0023] The lower surface of the sole is radiused at the verticalthickest point about a line generally connecting the midpoints of awearer's first and second metatarsal-phalangeal joints.

[0024] “Radiusing” means the providing of a generally cylindricalcurvature to the surface about a linear axis. This radiusing produces asole with a forefoot region which is thinner on either side of thevertical thickest part along the longitudinal axis but is generally ofeven vertical thickness across a horizontal width about perpendicular tothe longitudinal axis. This radiused section must be at least 10 mm widein a shoe built on a last of net length 290 mm, measured along thelongitudinal axis, to provide an adequate rolling action. This minimumwidth of the radiused section is reduced or enlarged in directproportion to the length of the last bottom used to construct a sole. Asdescribed below, an appropriate radius length would be in the range 15to 150 mm in a shoe with an upper sole surface length of about 275 mm.As indicated above, the curvature approximates the curvature of acircular cylinder, but may describe a curve which is slightly ellipticalor has variable or other curvature which approximates a circular curve.

[0025] Distal to the radiused portion, the lower surface of the sole mayhave any of a variety of shapes, including curvatures of differentradii.

[0026] The sole may be made of a great number of different materials,foams such as ethylene vinyl acetate (EVA) or polyurethane (PU) with arubber lower surface would be one possible form. Since the geometry ofthe sole is the crucial element in its function, a great many othercombinations may be envisaged. For example; injection molded plastics,metal, carbon fiber, solid rubber, wood, other composites or polymerscould be used as elements or as the entirety of the sole structure. Theupper may be made of any material and may be structured in any of themany known forms in the footwear industry.

[0027] The sole functions by providing a fulcrum about which thewearer's foot rotates during exercises characterized by such actions asrunning, jumping or power walking which include a contraction of theposterior muscles of the lower leg. This fulcrum is in the form of athickened forefoot which does not prevent the wearer's heel fromreaching an equal or lower position than their forefoot when the sole isin ground contact. The fulcrum is further defined by the lower surfacebeing curved on a radius generally about and aligned with a lineconnecting the mid points of a wearer's first and secondmetatarsal-phalangeal joints.

[0028] The term “generally”, as used herein refers to an approximatepositional relationship to other parts of the sole, article of footwear,or wearer's foot. However, it does not denote a precise position. Thus,for example, a line generally connecting the midpoints of the first andsecond metatarsal-phalangeal joints refers to a line approximatelythrough the mid-points of those joints, but not necessarily precisely.In part, the approximate relationship shows recognition that wearers'feet differ, so that the positions or regions of a manufactured sole inrelation to a wearer's foot will vary slightly depending on the shapeand size of the foot and the fit of the article of footwear to which thesole is attached or is an integral part.

[0029] Thus, in a first aspect the sole has an upper and lower surface,and a thickness between the upper and lower surfaces. The thickness hasa greatest vertical thickness in the forefoot region. The lower surfaceof the sole has a generally cylindrical curvature below the greatestthickness; the axis of the cylindrical curvature generally passesthrough the mid-points of the first and second metatarsal joints of awearer's foot.

[0030] In a second aspect, the sole has an upper surface, a lowersurface, a longitudinal axis, and a thickness between the upper surfaceand the lower surface. When the sole is part of an article of footwearor attached to an article of footwear, the article of footwear has alength defined by the distance from the terminal heel portion to theterminal toe portion. The thickness has a greatest vertical measurementat a point which is approximately 55-90% of the length measured alongthe longitudinal axis. The lower surface has a generally cylindricalcurvature below the greatest thickness; the axis of the cylindricalcurvature is oriented generally parallel to the upper surface of thesole, and at an angle of between 78° and 102° to the longitudinal axis.

[0031] In a related aspect, the sole has an upper surface having a rearedge, a front edge, and a length between the front and rear edges. Thesole also has a lower surface, a thickness between the upper and lowersurfaces, and a longitudinal axis. The thickness is greatest at a pointbetween about 55% and 90% along the length measured from the rear edgealong the longitudinal axis. The lower surface has a generallycylindrical curvature below the greatest thickness. The cylindricalcurvature has a radius about a generally linear axis. The orientationand dimensions of the axis and radius of the cylindrical curvature areas described for the preceding aspect.

[0032] In a fourth aspect, the sole has an upper surface, a lowersurface, and a thickness between the upper lower surfaces. The sole hasits greatest thickness generally below the first and secondmetatarsal-phalangeal joints of a wearer's foot. The lower surface has agenerally cylindrical curvature below the greatest thickness; thecylindrical curvature is generally radiused about a line passing throughthe mid points of the first and second metatarsal-phalangeal joints ofthe wearer's foot.

[0033] In preferred embodiments of the above aspects, the sole mayphysically have a heel region, a midfoot region, a forefoot region, anda toe region, or one or more of the regions other than the forefootregion may physically be absent. Thus, in a preferred embodiment, in useat least the forefoot of a foot of a wearer rests on the upper surfaceof the sole. Also in a preferred embodiment, the sole is attached to anexisting article of footwear. Also in preferred embodiments, the sole isfixedly attached to an upper to form an article of footwear; the uppermay be adapted to fit over an existing article of footwear. Also inpreferred embodiments, the sole is attached to at least one strap; theupper surface is at least partially bounded by a strap; the soleincludes a midsole and an outsole; the lower surface is wider than theupper surface at at least one point; the lower surface includes at leasta portion lying in a plane tangential to the cylindrical curvature; thethickness includes at least one pillar; the sole includes a midsole madeof a material selected from EVA, PU, wood, hard plastic, and spongerubber; the thickness includes a rigid shank; the thickness includes atleast one undercut; the lower surface includes a laterally inclinedbevel, the lower surface includes a reinforcing shank; and the uppersurface is at least partially bounded by a cupsole.

[0034] Other features and advantages of the invention will be apparentfrom the following description of the preferred embodiments and from theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035]FIG. 1 is a side elevational view of an article of footwear inaccordance with the present invention.

[0036]FIG. 2 is a vertical, transverse sectional view through the heelof the shoe of FIG. 1.

[0037]FIG. 3 is a vertical, transverse sectional view through theforefoot of the shoe of FIG. 1.

[0038]FIG. 4 is a top plan view of the sole of the shoe of FIG. 1.

[0039]FIG. 5 is a top plan view of the sole of the shoe of FIG. 1,illustrating the location of the line connecting the midpoints of thefirst and second metatarsal-phalangeal joints.

[0040]FIG. 6 is a schematic side elevational view of an article offootwear in accordance with the present invention illustrating thelocation of the line connecting the midpoints of the first and secondmetatarsal-phalangeal joints.

[0041]FIG. 7 is a diagrammatic representation of an embodiment of anarticle of footwear in accordance with the present invention.

[0042]FIG. 8 is a diagrammatic representation of an embodiment of anarticle of footwear in accordance with the present invention.

[0043]FIG. 9 is a vertical, transverse sectional view through the heelof the shoe of FIG. 8.

[0044]FIG. 10 is a vertical, transverse sectional view through theforefoot of the shoe of FIG. 8.

[0045]FIGS. 11, 12, 13 and 14 are side elevational views of articles offootwear in accordance with the present invention.

[0046]FIG. 15 is a bottom plan view of the article of footwear of FIG.14.

[0047]FIGS. 16, 17, and 18 are side elevational views of articles offootwear in accordance with the present invention.

[0048]FIG. 19 is a bottom plan view of the sole of FIG. 18.

[0049]FIG. 20 is a vertical, transverse sectional view through themidfoot of the sole of FIG. 19.

[0050] FIGS. 21A-C are front elevational view, side elevational view andtop plan view of a sole in accordance with the present invention.

[0051]FIG. 22 is a side elevational view of an article of footwear inaccordance with the present invention.

[0052]FIG. 23 is a vertical, transverse sectional view through the heelof the shoe of FIG. 22.

[0053]FIG. 24 is a vertical, transverse sectional view through theforefoot of the shoe of FIG. 22.

[0054] FIGS. 25A-C are side elevational views of a sole of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] Referring to FIG. 1, an upper 30 may be of any form desired. Theupper 30 is any mechanism suitable for holding the sole of thisinvention in position on the foot of a wearer during use. A specificexample for this preferred embodiment includes a leather vamp andquarter 31 with a U-throat opening 33. Lace holes 28 are provided fordrawing the upper 30 closed about the foot with a lace (not shown). Theupper 30 is secured to the top surface of the sole 32 by cement and bythe inclusion of a lasting board 40 (see FIG. 2) in a California sliplast construction. Any other methods and constructions may be used forthe forming of an upper and its attachment to the sole of thisinvention. For example, string lasting, flat cement lasting, moccasinconstruction or welting may be employed. The upper 30 may be directlyinjection molded with a sole, a series of foot encompassing straps maybe attached to the sole, the sole may be attached by stitching,stapling, nailing or solvent bonding.

[0056] The upper surface of the sole 32 corresponds to the profile of alast used for the construction of the shoe. The only essential part ofthe upper surface of the sole 32 is that part below the forefoot of awearer.

[0057] A midsole 34 of firm resilient EVA foam is provided between theupper 30 and the ground 42 contacting rubber outsole sections 36 and 38.A hardness of Shore ‘C’ 60 or higher is desirable for the midsole 34. Itis possible to make the midsole in any of a great many ways andmaterials, including blow molding or injection molding plastics,composites, leather, PU, sponge rubber, wood, cork or metal.

[0058] The outsole sections 36 and 38 may alternatively be made ofmaterial such as reground urethane, PU, polyvinyl chloride (PVC),synthetic rubber or rubber-like polymers. Another possible form combinesthe midsole 34 and outsole 36, 38 into a single unit of manufacture,such as a solid rubber, PU or EVA molded sole. The term sole is used inthis patent to encompass all combinations of parts to form the geometricsole shape required for the functioning of this invention.

[0059] Referring to FIG. 2, the heel region includes parts of the upper30 and lasting board 40 attached to the upper surface 32 of the sole bycement. This preferred embodiment includes a portion of the midsole 34forming a wrap 44 onto the upper 30 to increase security of the bond andaid in stabilizing the wearer's heel during use of the shoe.

[0060] The midsole 34 and wrap 44 may be formed by compression moldingof EVA foam. The outsole 38 is wider than the upper surface 32 of thesole to provide a stabilizing benefit during heel to ground contact.Outsole 38 may be attached to the midsole 34 with cement. The outflaring of midsole 34 to make a pyramidal shape is not obligatory andmay be left off to decrease weight or reduce costs.

[0061] Referring to FIG. 3, the upper 30 and lasting board 40 areattached to the upper surface 32 of the sole. The midsole 34 forms awrap 46 onto the upper 30 to improve bonding and increase stability ofthe forefoot during jumping motions. The outsole 36 is generally a sheetof thin rubber including a tread pattern. Alternatively the outsole 36may include lugs or cleats to engage the ground 42 and enhance traction.Outsole 36 may be made by compression molding of rubber.

[0062] Referring to FIGS. 4 and 5, the sole has an upper surface 32, afront edge of the sole upper surface 47 and a rear edge of the soleupper surface 49. The sole of a wearer's foot rests upon the sole uppersurface 32 during use. The upper surface 32 has a longitudinal axis 50.The upper surface 32 generally corresponds to the bottom net of the lastused for the manufacture of the article of footwear. The longitudinalaxis 50 runs about from the middle of the heel region through about themiddle of the forefoot region.

[0063] The first metatarsal 58 joints with the first phalange 62. Thesecond metatarsal 60 joints with the second phalange 64. A line 56 maybe drawn to connect the mid points of the first and secondmetatarsal-phalangeal joints. The sole has its greatest verticalthickness generally below the line 56. The line 56 lies between 8 and 25mm above the bottom surface of the wearer's foot in a shoe of uppersurface 32 length about 275 mm.

[0064] The lower surface of the sole is radiused about the line 56 sothat the ground contacting portion of the forefoot region outsole 36curves away from the ground on either side of the thickest vertical partof the sole when measured along the longitudinal axis 50. The radiusingprovides a generally cylindrical curvature to the surface with line 56as a linear axis. The radius length of the lower sole surface verticallybelow line 56 is calculated by adding the thickness of the outsole 36,the midsole 34, lasting board 40, the thickness of any other shoecomponents included below the forefoot of the wearer and the height ofthe line 56 above the sole of the wearer's foot. In the preferredembodiment, the radius would be about 65 mm. An appropriate radius valuewould be in the range 15 to 150 mm in a shoe with an upper sole surface32 length of about 275 mm.

[0065] The height of the line 56 above the sole of the wearer's foot maybe approximated by the addition of between 8 and 25 mm for shoes with asole upper surface 32 length of about 275 mm. This figure of 8 to 25 mmmay be prorated for foot size by adjusting in proportion to the lengthof the sole upper surface 32. The outside range of figures for theheight of the line 56 above the sole of the foot for adult wearer's feetis 4-30 mm.

[0066] The greatest thickness of the sole is generally constant acrossthe width of the sole below the line 56. Due to variations inindividual's feet, the exact position of the line 56 and its angle tothe longitudinal axis 50 will vary. The lines 52 and 54 show possibleplaces for the line 56 in individuals with either short or long toes.The lines 52 and 54 are shown as being about perpendicular to thelongitudinal axis 50 but a variation in angle of plus or minus up to 12°may be present between different individuals. The line 56 will fallgenerally in the range delineated by lines 52 and 54. The line 56 willbe inclined in the range 780°-102° to the longitudinal axis of the shoe.The position of the calcaneous 66 is a marker of the general position ofthe heel region of the sole.

Other Embodiments

[0067] Other embodiments are within the following claims. For example,referring to FIG. 6, an upper 30A is shown about a medial X-ray view ofa wearer's foot resting on the upper surface 32A of a sole of thisinvention. The first phalange 62 and first metatarsal 58 meet at a jointas do the second phalange 64 and the second metatarsal 60. The line 56joins the mid points of the first and second metatarsal-phalangealjoints and is shown in end view passing into the plane of the drawing.

[0068] The sole 35 is vertically thickest below line 56 and the radiusedlower sole surface 72 is radiused about line 56. This radiused lowersole surface 72 extends at least 5 mm on either side of line 56 alongthe longitudinal axis of the shoe with a sole upper surface of 290 mm inlength. The radiused section may be made longer than this but functionwill be lost if it is made shorter. In shoes built with a shorter uppersurface length, the length of the radiused sole 72 may be reducedproportionally.

[0069] The sole 35 has more sharply angled walls 74 to give pleasingcosmetic effects and reduce the total volume of material thus savingcosts and weight. The sole includes a heel 70 with a lower surface 68aligned tangentially with the radiused lower sole surface 72. Thisprovides a maximum area of sole to ground contact when the wearer'scalcaneous 66 is pushed down while the radiused lower sole surface 72 isin contact with the ground 42.

[0070] Referring to FIG. 7, a shoe with upper 30B is furnished with arubber cupsole 76, a pillar 78 of rigid rubber or foam and a radiusedplate 80 with a ground contacting lower sole surface 73.

[0071] Referring to FIG. 8, an upper 30C has a sole 35C such that thetoe and forefoot region lower sole surface 82 is cylindrically curvedabout an axis through the first and second metatarsal-phalangeal jointmid points. The radius of the lower sole surface 82 is just great enoughfor the sole 35 c to wrap onto the upper 30 c at the front of the toeregion. The midfoot and heel lower sole surface 84 is tangential to theradius of the forefoot lower sole surface 82.

[0072] Referring to FIGS. 9 and 10, in one embodiment, the sole 35Cincludes a sole wrap 44C on to the upper 30C to a level above the topsurface 32C of the sole and the lasting board 40C. The heel sole lowersurface 84 is wider than the sole upper surface 32C which results inoutflared sidewalls 86. The forefoot sole lower surface 82 is wider thanthe sole upper surface 32C which results in outflared side walls 88.

[0073] Referring to FIG. 11, one embodiment of the present inventionincludes a sole 92 with an upper surface 95 and lower surface 94. Astrap system 96 formed of elastic gore, nylon web, neoprene spandex orother appropriate materials holds the sole 92 in place below a wearer'sexisting shoe 90. The sole 92 is held in position on the shoe 90 so thatthe combined vertical thickest part of the sole 92 and shoe sole 90 isbelow a line passing through the mid points of the wearer's first andsecond metatarsal-phalangeal joints. The surface 94 is cylindricallycurved to make rolling contact with the ground 42 when the wearer's calfmuscles contract.

[0074] Referring to FIG. 12, In one embodiment, an existing upper 90Dhas a sole 92D attached with adhesive as a replacement sole. Any excesscement may be hidden by a cupsole 98. The function is provided by theradiused forefoot sole lower surface 94D as it contacts the ground 42.

[0075] Referring to FIG. 13, an upper 30E is attached to the uppersurface 32E of the sole 35E. The forefoot and toe region sole lowersurface 72E is of sufficient radius to wrap onto the upper 30E at thefront of the shoe. The sole 35E has a midfoot cut-out 104 to reduceweight. The heel region sole lower surface 102 is aligned tangentiallywith the radius of lower surface 72E. The rear of the heel 100 isrounded and a cushioning element is included in the midsole 34E toattenuate shock as the heel strikes the ground 42. Suitable cushioningelements include EVA or PU foam, air bags, gel bags or Hytrel springs.

[0076] Referring to FIGS. 14 and 15, an upper 30F is attached to a sole35F with very thin sections in the heel 106 region, midfoot 108 regionand the toe 110 region to reduce weight. Suitable materials wouldinclude hard rubber, plastic or composites. A thicker sole 35F isprovided in the forefoot region with a radiused lower surface 72F tomake contact with the ground 42. Weight is further reduced by undercuts112 in the sole 35F. An undercut is an area of the side wall connectingthe upper surface of the sole and the lower surface of the sole devoidof material.

[0077] Referring to FIG. 16, upper 30G is attached to a sole 35G whichfeatures a radiused forefoot lower surface 72G contacting the ground 42in use. The sole midfoot lower surface 114 is tangential to the radiusof lower surface 72G. Very thin material is provided in the heel 106Gand toe 110G regions. Sheet steel or carbon fiber epoxy composites wouldsuffice for heel 106G and toe 110G. The sole 35G includes a wrap 46Gonto the upper 30G.

[0078] Referring to FIG. 17, different shoes built with the same sizedupper 30H may be manufactured with different sole lower surfaces 116,118 or 120. Whilst the radii of the three soles are different, thecenter of rotation and longitudinal alignment are the same. The solesmay be attached with a cupsole front wall 76H. The smaller radius lowersurface 116 would be used by beginners, the medium radius lower surface118 would be used by intermediate level athletes and the large radiuslower surface 120 would be used by advanced athletes.

[0079] Referring to FIGS. 18, 19 and 20, an upper 30J is attached to asole 35J by direct injection to produce bonding to the upper surface ofthe sole 32J, a wrap 44J in the heel region and a wrap 46J in the toeregion. The sole in the heel region 70J includes a laterally inclinedbevel 122 and a lower surface 68J tangential to the radius of theforefoot sole lower surface 72J. Weight is reduced by an under cut 112Jin the toe region and by cutting material out of the midfoot to leaveonly a reinforcing shank 124. Sole 35J stiffness in the midfoot isfurther enhanced by wraps 126 onto the upper 30J.

[0080] Referring to FIGS. 21A-C, an upper 30K is attached to a sole 35Kwith a large radius to the sole and forefoot lower surface 82K. Thelarge radius provides a smooth transition into a wrap 134 onto the upper30K above the sole upper surface 32K. To stabilize the thicker solearising from the larger radius, the sole lower surface edge 130 isextended backwards at the heel 128 and is made wider across the forefootregion relative to the sole upper surface edge 132.

[0081] Referring to FIGS. 22, 23 and 24, an upper 30L is attached to afoam cup 136 with an upper sole surface 32L below the lasting board 40L.The foam cup 136 is inserted into a composite or molded plastic rigidshank 138. The shank weight is reduced by inclusion of an air space 142.A lower foam sole 140 is inserted in the rigid shank 138 and equippedwith rubber outsole sections 38L in the heel and 36L in the forefoot.The forefoot lower sole surface 72L is cylindrically curved or radiusedabout a line passing through the first and second metatarsal-phalangealjoints of a wearer and contacts the ground 42.

[0082] Referring to FIGS. 25A-C, sole 143 has a generally flat uppersurface 144, a heel 146 and a radius to the lower surface 72M about theline 56 to make rolling contact with the ground 42.

Operation of Invention

[0083] Referring to FIGS. 1,2, 3, 4 and 5, the midsole 34 and outsole 36form the complete sole which functions by providing a fulcrum aboutwhich the wearer's foot rotates. This rotation is generated duringexercises characterized by such actions as running, jumping or powerwalking which include a contraction of the posterior muscles of thelower leg. This fulcrum allows the heel to reach an equal or lowerposition than the forefoot when the sole is in ground 42 contact. Thispermits a full range of motion of the ankle and calf muscles. Thisfunction is achieved by making the vertical thickness of the forefootmidsole 34 and outsole 36 shown in FIG. 3 equal or greater than thetotal thickness of the heel midsole 34 and outsole 38 shown in FIG. 2.

[0084] The fulcrum is further refined by the lower surface of theoutsole 36 being generally cylindrically curved with an axis of line 56.Line 56 connects the mid point of a wearer's first metatarsal 58 andfirst phalange 62 joint to the mid point of a wearer's second metatarsal60 and second phalange 64 joint. This permits a natural rolling forwardof the sole as the calf muscle is contracted. The resistance will befairly constant due to the constant length of the lever arm between theupper surface of the sole 32 under the forefoot and ground 42. Thisarrangement also causes line 56 to stay about a constant distance fromground 42 during the forward rolling motion of the sole. Improvedstability is offered by wrapping the midsole 34 onto the upper 30 toform a lip, bead or wrap 44 in the heel or wrap 46 in the forefoot.

[0085] Referring to FIG. 6, the radiused lower surface 72 of sole 35 islimited in extent to allow interesting cosmetic shaping of the walls 74.A heel 70 may be provided with a sole lower surface 68 set tangentiallywith the radius of the sole lower surface 72. This gives a maximal areaof lower surface 68 contact and support when the heel 70 and forefootlower surface 72 are in ground 42 contact simultaneously. Thisarrangement also reduces wear of the lower surface 68.

[0086] Referring to FIG. 7, the pillar 78 contributes to the verticalthickness in the forefoot region. Pillar 78 is terminated by plate 80with a lower surface 73.

[0087] Referring to FIG. 8, the sole 35C is has flared walls 86 and 88in the heel and forefoot respectively, to enhance stability. The solelower surface 84 extends through the heel and midfoot to join theradiused sole lower surface 82 tangentially in the forefoot. This addstorsional rigidity and shank stiffness. This embodiment also results inan increased surface area of the lower surface 84 providing greaterabrasion wear resistance.

[0088] Referring to FIG. 11, It is sometimes desirable to wear atraditional type of shoe in athletic training and change shoes forperiods of plyometric training. The strap structure 96 or analogousattachment systems well know in the footwear industry such as hook andloop closures or neoprene spandex bags, allow the temporary addition ofthe sole of this invention to a traditional is shoe 90. The radius ofthe overshoe sole 92 is manufactured to align the center of rotation ofthe cylindrically curved lower surface 94 with the line joining the midpoints of a wearer's first and second metatarsal-phalangeal joints. Thethickness of a traditional sport shoe sole under the forefoot is in therange 3 to 15 mm which is allowed for in the thickness of the sole 92during production.

[0089] Referring to FIG. 12, it is a common practice to resole worn outtraditional sport shoes. This resoling may be done with a sole of thisinvention such as the sole 92D with a cupsole 98 construction and aradiused sole lower surface 94D. The existing sole of the worn upper 90Dis heat striped, an adhesive applied to the sole upper surface of sole92D and the lower surface of the upper 90D and the two surfaces broughttogether while the adhesive is still tacky.

[0090] Referring to FIG. 13, material is removed from the midfoot with acut out 104. This may be done by molding the foam or physically cuttingout a section of the structure. Rounding the rear border of the heel 100reduces sole wear in this area if the heel strikes the ground duringrapid forward motion with the toes fully elevated. This structure alsoimproves the forward rolling action of the foot to bring the heel solelower surface 102 and forefoot sole lower surface 72E smoothly intocontact with the ground.

[0091] Referring to FIGS. 14 and 15, sole weight may be reduced byoffering a form with the heel 106, midfoot 108 and toe 110 regionsdevoid or nearly devoid of the sole 35F. The weight may be furtherreduced by cutting or molding the sole 35F with undercuts.

[0092] Referring to FIG. 16, it is possible to reduce weight and stillsupport the shank with the sole 35G and wraps 46G by leaving the heel106G and toe 110G regions devoid or nearly devoid of sole 35G.

[0093] Referring to FIG. 17, as the length of the radius in the soleforefoot of this invention is increased, the moment of inertia of thewearer's body will be increased, requiring additional work to roll theshoe forward. This biomechanical fact can be used advantageously byoffering shorter radius soles, such as the one bounded by sole lowersurface 116, for less strong athletes. As the athletes gain in strength,progressive resistance is needed to continue the improvements associatedwith physical training. This additional resistance may be provided bychanging to a sole of longer radius in the forefoot, such as onedelineated by lower sole surface 118 or 120.

[0094] Referring to FIGS. 18, 19 and 20, in running type motions, thefoot is slightly supinated during the swing phase. This can result inlanding on the posterio-lateral aspect of a heel and increase wear atthat point. Providing a laterally facing heel bevel 122, this weareffect may be mitigated. As an athlete tires in training, they may allowthe foot to collapse in the midfoot area. This is resisted by the shankstiffness of the shoe in the midfoot area which may be increased byincluding a reinforcing rib 124 connecting the heel and forefoot regionsof the sole 35J.

[0095] Referring to FIGS. 21A, 21B and 21C, using a large radius forsole toe and forefoot lower surface 82K provides a constant lever armduring movements that keep the sole in contact with the ground and thereis extreme plantar flexion of the foot.

[0096] Referring to FIGS. 22, 23 and 24. There are many possiblestructures that meet the geometric requirements of this invention andprovide the intended biomechanical action. One example includes a carbonfiber composite or injection molded rigid shank 138 that has upper foamelement 136 inserted for attaching the upper 30L and a lower foamelement 140 inserted to retain heel outsole 38L and forefoot outsole 72Lsections. The rigid shank 138 maintains the torsional stiffness of thesole during use.

[0097] Referring to FIGS. 25A-C, as a wearer's calf muscles contract,the lower surface 72M rolls forward along the ground 42. The heel 146 israised and the line 56 (shown here in end view) joining a wearer's firstand second metatarsal-phalangeal joints remains generally at the sameheight above the ground 42 through the full range of motion.

[0098] Thus the reader will see that the exercise sole of the inventionprovides a full range of motion for the ankle in exercise, provides acontinuous rolling motion for the foot, aligns this forefoot rollingmotion with the primary axis of force exertion in jumping and provides aforefoot sole radius length appropriate for exercise of the calfmuscles. The sole of the invention further reduces the forefoot toground slapping action, scales the sole radius according to bodydimensions and reduces the rubbing away that occurs in relatively flatsoles.

[0099] While the above description contains many specificities, theseshould not be construed as limitations on the scope of the invention,but rather as an exemplification of one preferred embodiment thereof.Many other variations are possible. For example, a shell molded uppermay have a sole of this invention attached by rivets or screws, the solemay be more flared medially than laterally, stabilizing side springs maybe attached to the sole side walls, the lasting board may be furnishedwith tabs or extensions cut from the same sheet without stitching andupper components attached thereto, the sole may be used without anyupper for a user to stand upon as an exercise device or the outsole mayhave cushioning benefit provided by an A-Frame sole structure.Accordingly, other embodiments are within the scope of the invention andthe claims.

What we claim is:
 1. A sole comprising: an upper surface, a lowersurface, and a thickness between said upper surface and said lowersurface, and wherein said thickness has a greatest vertical thickness inthe forefoot region of said sole, and said lower surface has a generallycylindrical curvature below said greatest vertical thickness, saidcylindrical curvature having as an axis a line passing generally throughthe mid points of the first and second metatarsal-phalangeal joints-of awearer's foot.
 2. The sole of claim 1, wherein said sole comprises aheel region, a midfoot region, a forefoot region and a toe region.
 3. Asole comprising: an upper surface having a rear edge, a front edge and alength between said rear edge and said front edge, a lower surface, alongitudinal axis, and a thickness between said upper surface and saidlower surface, wherein said thickness has a greatest thickness at apoint between 55% and 90% along said length measured from said rear edgealong said longitudinal axis, said lower surface has a generallycylindrical curvature below said greatest thickness, said cylindricalcurvature has a radius about a generally linear axis, wherein saidradius is equal to said greatest thickness plus an amount in the rangefrom 4 to 30 millimeters, and said linear axis is oriented generallyparallel to said upper surface and at an angle to said longitudinal axisin the range from 78° to 102°.
 4. A sole comprising: an upper surface, alower surface, a longitudinal axis, and a thickness between said uppersurface and said lower surface, wherein when said sole is a part of orattached to an article of footwear, said article of footwear has alength described by a line from approximately the terminal heel portionto the terminal toe portion of said article of footwear, wherein saidthickness has a greatest thickness at a point between 55% and 90% alongsaid length measured from said terminal heel portion along thelongitudinal axis of said article, said lower surface has a generallycylindrical curvature below said greatest thickness, said cylindricalcurvature has a-radius about a generally linear axis, wherein saidradius is equal to said greatest thickness plus an amount in the rangefrom 4 to 30 millimeters, and said linear axis is oriented generallyparallel to said upper surface and at an angle to said longitudinal axisin the range from 78° to 102°.
 5. A sole comprising: an upper surface, alower surface, and a thickness between said upper surface and said lowersurface, wherein said thickness has a greatest thickness generally belowa first and a second metatarsal-phalangeal joint of a wearer's foot, andsaid lower surface has a generally cylindrical curvature below saidgreatest thickness and said cylindrical curvature is generally radiusedabout a line passing through the mid points of said first and saidsecond metatarsal-phalangeal joints.
 6. The sole of claim 1, wherein atleast the forefoot of a foot of a wearer rests upon said upper surfaceduring use.
 7. The sole of claim 1, wherein said sole is fixedlyattached to an upper to form an article of footwear.
 8. The article offootwear of claim 7, wherein the upper is adapted to fit over anexisting article of footwear.
 9. The sole of claim 1, wherein said soleis attached to at least one strap.
 10. The sole of claim 1, wherein saidupper surface is at least partially bounded by a wrap.
 11. The sole ofclaim 1, wherein said sole includes a midsole and an outsole.
 12. Thesole of claim 1, wherein said lower surface is wider than said uppersurface at at least one point.
 13. The sole of claim 1, wherein saidlower surface includes at least a portion lying in a plane tangential tosaid cylindrical curvature.
 14. The sole of claim 1, wherein saidthickness includes at least one pillar.
 15. The sole of claim 1, whereinsaid sole includes a midsole made of a material selected from EVA, PU,wood, hard plastic, and sponge rubber.
 16. The sole of claim 1, whereinsaid thickness includes a rigid shank.
 17. The sole of claim 1, whereinsaid thickness includes at least one undercut.
 18. The sole of claim 1,wherein said lower surface includes a laterally inclined bevel.
 19. Thesole of claim 1, wherein said lower surface includes a reinforcingshank.
 20. The sole of claim 1, wherein said upper surface is at leastpartially bounded by a cupsole.